Evaluation of standard physico-chemical and rheological parameters in predicting bread-making quality of durum wheat (Triticum turgidum L. ssp. durum [Desf.] Husn.)

The efficacy of empirical rheological methodology for modern Triticum aestivum L. in predicting bread-making quality in Triticum turgidum L. ssp. durum is warranting of attention. The present study was aimed at providing a comparative evaluation of an array of standard rheological tests in predicting bread quality in three modern cultivars (Core, Sant’Agata and Simeto) and three durum wheat landraces (Ruscìa, Timilìa and Tumminia SG3). Gluten strength, alveograph dough strength and tenacity/extensibility ratio, farinograph stability and mixograph peak dough height and overall score, were significantly higher in the modern cultivars, and distinctive in accounting for the variance between modern and old genotypes, using principal component analysis. Quality bread-making parameters, including bread volume, height and specific volume, were significantly higher in the durum wheat landraces. Standard rheological parameters were ineffective in predicting bread quality, necessitating the requisite in redefining rheological parameters to meet the increasing interest in heritage durum wheat genotypes for bread-making.     

Hearth bread baking quality of durum wheat varying in protein composition and physical dough properties

Thirty durum wheat genotypes from ten countries of origin were grown in field plots for two consecutive years. Three of the genotypes were γ‐gliadin 42 types and the remainder were γ‐gliadin 45 types. Among the γ‐gliadin 45 types, six high‐molecular‐weight glutenin subunit (HMW‐GS) patterns were identified: 6 + 8, 7 + 8, 7 + 16, 14 + 15, 20 and 2*, 20. All the γ‐gliadin 42 genotypes contained low amounts of unextractable polymeric protein (UPP) and exhibited low gluten index values and weak gluten properties. The γ‐gliadin 45 genotypes exhibited a wide range of UPP, gluten index and dough strength. HMW‐GS 20 genotypes were generally weak, whereas HMW‐GS 6 + 8 and 7 + 8 genotypes were generally strong. When baked by a lean formulation, long‐fermentation straight‐dough hearth bread process, the durum wheat genotypes exhibited a wide range of baking quality. Loaf volume and bread attributes were strongly correlated with UPP and gluten index. Some of the genotypes exhibited bread attributes and loaf volume equal or slightly superior to those of a high‐quality bread wheat flour. However, even the strongest durum wheat genotypes exhibited inferior fermentation tolerance to the bread wheat flour, as seen by a requirement for lower baking absorption during dough handling and more fragile dough properties when entering the oven. Among the HMW‐GS groups, HMW‐GS 7 + 8 and 6 + 8 exhibited the best and HMW‐GS 20 the poorest baking quality. Farinograph, alveograph and small‐scale extensigraph properties demonstrated that a combination of dough elasticity and extensibility was needed for superior durum wheat baking performance. Copyright © 2007 Society of Chemical Industry     

Effects of lipoxygenase and of chemical oxidising agent potassium iodate on rheological properties of durum dough

To study the involvement of lipoxygenase (LOX) and oxidising agent potassium iodate (KIO₃) in rheological behaviour of dough, mixograph and alveograph tests were performed using durum cultivars differing for quality and endogenous levels of LOX. Both tests were done in standard condition and with the adding of KIO₃ and of LOX and/or its substrate, utilised singly or in different combinations. The effects of these treatments were related to change of ‐SH and S–S content in relative mixograph dough. The mixograph and alveograph responses showed that the KIO₃ had an improving effect on dough tenacity and that the adding of LOX system enhanced this trend; on the contrary, the LOX system alone seemed not affect mixing stability. No relation was found between rheological responses and ‐SH and S–S content in the mixograph doughs. The results obtained could suggest that in durum wheat the main effect of LOX could be ascribable to bleaching action because of the co‐oxidation of carotenoid pigments.     

An application of linear regression technique for predicting bulgur yield and quality of wheat cultivars

Grains of 26 Turkish wheat cultivars and advanced breeding lines were used in this study. Simple correlations between a number of quality parameters to predict bulgur yield and bulgur cooking quality were determined. Highly significant correlations between bulgur yield and each of the thousand-kernel weight and the sum of the grain over 2.8 + 2.5 mm sieves were obtained for both durum and bread wheat samples (p < 0.01). The regression equations showed that the models involving two variables (the thousand-kernel weight and the thickness of the grain for durum wheat samples; the thousand-kernel weight and the length of the grain for bread wheat samples) resulted in the highest R2 values. For an assessment of the influence of all factors on bulgur cooking properties (total organic matter: TOM and colorimetric test values), simple and multiple regression analyses were used to find equations that predict best the relationship between various quality parameters and bulgur cooking properties. The models involving two variables; the vitreousness and the dry gluten contents for the durum wheat samples and SDS sedimentation test value and wheat protein content for the bread wheat samples resulted in the highest R2 for the TOM value.     

A finer screening of wheat cultivars based on comparison of the baking potential of whole‐grain flour and white flour

Between 2007 and 2009, 160 wheat samples were harvested at four growing locations in Quebec (Eastern Canada) and evaluated individually for their performance in whole‐grain bread (all grain fractions) and white bread prepared with a long‐fermentation process (3 h). Combination of results from both baking tests allowed the most complete evaluation of the gas retention capacity of wheat samples. Compared to cultivar and crop year, growing location had a minor effect on the overall bread making potential of wheat samples. In whole‐grain bread, the four winter wheat lines had a poorer performance than the twenty‐one spring wheat cultivars. Little correlation was seen between dough mixing stability and gas retention properties. Determination of strong gluten content (dry gluten × gluten index) might be a useful screening tool for early‐generation wheat cultivars.     

Environmental conditions affect semolina quality in durum wheat (Triticum turgidum ssp. durum L.) cultivars with different gluten strength and gluten protein composition

BACKGROUND: Sowing time may impact semolina and pasta cooking quality by changing the environmental conditions during grain filling. The effect of an optimum and a delayed sowing time on semolina quality was studied by comparing six cultivars under irrigation, in order to isolate temperature from drought effects. RESULTS: Protein content was higher in the old cultivars and in the late sowings, according to the number of days with temperature between 30 and 40 °C during ripening. Gluten index increased as temperature rose to a threshold of about 30 °C, then decreased under higher temperatures. Mixograph parameters were less sensitive to high temperatures. Gliadin:glutenin correlated with gluten strength. Spaghetti firmness and protein content were positively correlated independently of sowing date. Cultivars Trinakria and Cappelli had the highest spaghetti firmness (900 and 828 g). CONCLUSIONS: Late sowings may represent a way of increasing pasta cooking quality whenever they place grain filling under thermal conditions able to increase protein percentage, although the accompanying decrease in yield may represent a drawback in environments prone to drought stress during ripening. The lower protein percentages of modern durum wheat cultivars under conventional sowing times results in a lower pasta cooking quality despite higher gluten strength. Published 2011 by John Wiley & Sons, Ltd.     

Impact of sourdough, yeast and gluten on small and large deformation rheological profiles of durum wheat bread doughs

The impact of percentage of sourdough (SD) addition and presence of yeast (Y) and/or commercial wheat gluten (G) -added singly and in binary combination- on both small and large deformation rheological performance and viscometric profile of durum wheat bread doughs was considered. Eight distinctive rheological dough features were identified as able/capable to clearly differentiate soured bread doughs made with semolina:remilled semolina rate of 80:20 into defined functional quality groups. The presence of added commercial wheat gluten provided firmer, more elastic and more extensible doughs with slightly lower viscometric profile. Simultaneous presence of yeast/sourdough and yeast/gluten modulate single effects of sourdough on the durum wheat bread dough mechanical properties. Several relationships were found between fundamental and empirical rheological properties and within viscometric features of soured semolina doughs.     

Comparative quality analysis of gluten strength and the relationship with high molecular weight glutenin subunits of 6 Tunisian durum wheat genotypes

Six Tunisian durum wheat genotypes (4 landraces and 2 improved) were evaluated for protein content, gluten strength, rheological characteristics, and HMW-GS patterns using a LabChip system. Variance analysis identified genotypic variation. The landraces Azizi, Mahmoudi, Chili, and Arbi exhibited the highest protein concentrations and gluten contents, and best dough tenacity and extensibility values. The Mahmoudi and Chili varieties had the highest protein contents (17.06 and 17.32% dry mass, respectively). Arbi and Chili had the highest gluten contents (60.88 and 60.59%, respectively). Azizi, Mahmoudi, and Chili were characterized by higher dough tenacity, lower dough extensibility, and a greater alveograph configuration ratio P/L. The high molecular weight glutenin subunits 6+8 (Azizi and Mahmoudi) and 7+15 (Chili), coded by the Glu-B1 locus, improved gluten strength and viscoelastic dough properties. Calculated HMW to LMW-GS ratios were within a narrow range of 0.17–0.29. Some genotypes have potential to be used as parents in breeding programs.     

Protein Characteristics that Affect the Quality of Vital Wheat Gluten to be Used in Baking: A Review

The use of vital wheat gluten in the baking industry and wheat flour mills aims to improve the rheological characteristics of flour considered unsuitable to obtain products such as sliced bread, French bread, high‐fiber breads, and other products that require strong flours. To improve characteristics such as flour strength, dough mixing tolerance, and bread volume, vital wheat gluten is added to flour at levels that can vary from 2% to 10% (flour basis), with 5% being a commonly used dosage. However, the vital wheat gluten commercialized in the market has few quality specifications, especially related to the characteristics of the proteins that constitute it and are responsible for the formation of the viscoelastic gluten network. Information on protein quality is important, because variations are observed in the technological quality of vital wheat gluten obtained from different sources, which could be associated to damage caused to proteins during the obtainment process. Several tests, either physical–chemical analyses, or rheological tests, are carried out to establish gluten quality; however, they are sometimes time‐consuming and costly. Although these tests give good answers to specify gluten quality, flour mills, and the baking industries require fast and simple tests to evaluate the uses and/or dosage of vital gluten addition to wheat flour. This review covers the concepts, uses, obtainment processes, and quality analysis of vital wheat gluten, as well as simple tests to help identify details about protein quality of commercial vital wheat gluten.     

Spaghetti cooking quality of waxy and non‐waxy durum wheats and blends

Quality attributes of waxy durum wheat (Triticum turgidum L), milled semolina and cooked spaghetti were examined and compared with those of two non‐waxy durum cultivars. With the exception of kernel hardness, wheat quality characteristics were similar for both waxy and non‐waxy durum. Compared with average values obtained for durum wheat grown in North Dakota (USA) during the crop year 2000, the values obtained for the wheat used in this study were equal or better for most parameters evaluated. Semolina extraction for all samples was lower than the 2000 average of 62.6%. The waxy lines had higher ash, lower speck count, similar protein quantity, lower wet gluten and stronger mixograph curves than the non‐waxy cultivars. Waxy durum semolina had higher lipid content, starch damage, stirring number and flour swelling values. Spaghetti made from waxy durum semolina had shorter cooking time, similar cooking loss and cooked weight and lower firmness values, which would be unacceptable by most standards. Spaghetti made from blends containing 20–80% waxy durum semolina were evaluated. Cooking time and firmness decreased and cooking loss increased as the amount of waxy semolina increased. Acceptable spaghetti was obtained using 20–40% waxy semolina blends, depending on the quality of the non‐waxy blending material. Copyright © 2004 Society of Chemical Industry     

马铃薯全粉在面条中的应用研究

将马铃薯全粉添加到小麦粉中,并辅助添加谷朊粉,制成马铃薯全粉面条。从质构特性、微观结构和面条的理化性质三个层面对三个不同马铃薯全粉添加比例的面条组别进行研究,发现马铃薯全粉对面团的力学性质,面筋网络的形成和构造以及面条的蒸煮参数和外观都会产生一定的影响。结果表明：马铃薯全粉添加量为20%（g/g）,谷朊粉添加为0.03%（g/g）时,总体指标最好;马铃薯全粉对面团的作用具有双向性,马铃薯淀粉对面团的影响偏负向,但是其中的多糖和蛋白质可能对面团和面筋网络有正向影响,同时谷朊粉的添加对面团的稳定性和面条的质量有改善作用。     

Statistical evaluation of different technological and rheological tests of Polish wheat varieties for bread volume prediction

Forty‐two Polish wheat flour were used to establish correlation coefficients between protein content, Zeleny test, falling number value, amylograph viscosity, farinograph water absorption, bread volume and rheological properties of dough, as shown by use of a extrusion chamber and alveograph. The equations expressing the changes of bread volume and flour water absorption as a function of significantly correlated parameters were calculated. The correlations and their significance depended on wheat quality and the alveographic parameters were significantly correlated with the dough extrusion parameters. The dough extrusion parameters were significantly correlated only with the water absorption of soft wheats. The dough rheological tests were correlated to a greater extent with the values of the Zeleny test than to the protein content. The prediction of the bread volume as a function of flour quality parameters and dough rheological properties was best done by grouping wheat varieties into specific qualitative classes.     

壳聚糖对小麦粉及其制品品质的影响

研究了壳聚糖对小麦粉面筋特性、面团流变学特性和面条蒸煮品质的影响。研究表明,添加适量的壳聚糖能够改善面团的流变学特性,使面团的吸水率明显增加,稳定时间和评价值也有一定程度的改善,面团的拉伸阻力增加,延伸性降低。添加量为0.8%时,改善效果最明显。同时,添加壳聚糖能在一定程度上改变面条的硬度、韧性,添加量为0.5%左右时,面条的硬度和韧性达到较好的平衡状态,随着添加量的增加,面条较硬,韧性较差。     

From ancient to old and modern durum wheat varieties: interaction among cultivar traits,management, and technological quality

Following the boom in durum wheat breeding, ancient wheat disappeared from the human diet and old durum wheat varieties were replaced by what is believed to be their better versions: higher yielding modern varieties grown in high-input systems. Breeders have worked intensely ever since to improve the quality of durum wheat traits – mainly gluten subunit alleles – to obtain superior technological quality in the main durum wheat end products (first pasta and then bread) but conflicts about predicting their quality still exist. This is because quality is neither governed by one trait alone nor conditioned by a single controllable factor. This review discusses the evolution of wheat varieties from ancient to old, and then modern durum wheat in terms of agronomy, genetics, technological, and end-product qualities. Environmental effects will not be discussed. Moving from ancient to modern durum wheat varieties, grain yield increased, grain protein concentration decreased, and gluten strength and dough toughness improved, ameliorating the quality of pasta but decreasing the durum wheat versatility. © 2018 Society of Chemical Industry     

蛋白质和淀粉对面团流变学特性和淀粉糊化特性的影响

以3个筋力不同的小麦粉为材料,利用分离重组方法,在保持小麦粉其他成分不变的情况下,组成不同面筋蛋白和淀粉含量的配粉,研究面筋蛋白和淀粉添加量对面团流变学特性和面粉糊化特性的影响。结果表明：随着面筋蛋白添加量的增加,3种筋力小麦粉配粉的面团稳定时间和粉质质量指数均呈升高趋势,峰值黏度、低谷黏度、最终黏度、稀懈值、回生值等总体呈下降趋势。小麦粉添加淀粉后,面团稳定时间和粉质质量指数均呈下降趋势,峰值黏度、低谷黏度、最终黏度、稀懈值、回生值等总体呈升高趋势。面筋蛋白和淀粉对小麦面团吸水率和面粉糊化温度的影响均较小。不同筋力小麦粉配粉各品质指标总体变化趋势一致,但变化幅度有一定差异。     

Rheological properties and baking quality of commercial durum wheat meals used to make flat crispy bread

Four commercial semolinas and four low-grade semolinas (LGS) samples were used in this study to make flat crispy bread (Carasau). The meals, doughs, and bread were compared with respect to a set of physical, chemical, and textural characteristics, and the bread evaluated by a trained sensory panel. LGSs had a higher extraction rate (higher ash content), finer granularity, and a higher damaged starch content than semolinas. The study revealed the key role of dry gluten content in determining hydration capacity of the dough, whereas damaged starch affected water absorption only in semolina samples. Gluten index and the ratio of gluten tenacity to extensibility (alveograph P/L) were significantly correlated with the weight of the dough discs following sheeting and molding. The panelists gave the highest quality score to the bread with the highest values of crackling and hardness. Textural and sensory attributes were both correlated with one another, and with gluten strength and tenacity, but not with the gluten content of the meal, which only affected final moisture content of the bread. Meal samples with a more tenacious and elastic gluten were more suited to produce flat crispy breads. The yellowness of durum wheat bread could not be predicted by measuring the color of the meal with a reflectance method.     

Rheological properties of gluten derived from wheat cultivars with identical HMW glutenin subunit composition†

Ten spring wheat cultivars possessing identical HMW glutenin subunits (2*, 7+8, 5+10) were evaluated for gluten and protein content. Gluten content was related to flour protein content (r=0·98). Addition of freeze-dried gluten to the base flour (cv Alpha) to a constant protein level of 12% generally increased dough strength. However, the magnitude of variation in mixing patterns depended more on the type of the supplemental gluten. Fortification of the base flour with the freeze-dried gluten from the cv Glenlea produced mixographs with the longest mixing development time (MDT), and highest band width energy (BWE) and energy to peak (ETP), suggesting that the source of gluten had a strong effect on dough rheology. The viscoelastic properties of undiluted wet gluten varied between cultivars during mixing reflecting differences in gluten quality. Freshly prepared wet gluten of Glenlea showed extended mixing tolerance as compared to Norseman or Alpha gluten. The wet gluten from cv Glenlea was less extensible with high maximum resistance to extension and had a larger area under the extensigraph curve than gluten obtained from cv Norseman. Gluten prepared from the cultivars Glenlea, Bluesky and Wildcat were less soluble in aqueous propanol and produced more froth when the dough was washed with deionised water. The froth proteins, separated by SDS-PAGE, predominantly contained strongly stained bands in the region corresponding to molecular weight <50 kDa. The rapid tests such as froth formation and alcohol solubility used in this study to discriminate various glutens were highly correlated with the mixograph parameters. These methods can be of practical value in evaluating gluten quality. © 1998 Society of Chemical Industry.     

Influence of wheat starch on rheological,structural and physico-chemical properties gluten–starch dough during mixing

This study mainly explored that the influence of wheat starch source on the rheology behaviours and structural properties of gluten–starch dough, and then the model doughs were prepared by the AK58 wheat gluten and three types of starches from strong (ZM366S), medium (AK58S) and weak gluten wheat (ZM103S) during mixing were studied. The damaged starch content of wheat starch was positively correlated with the wheat gluten strength, while the granule size was negatively. The G', G" and the extension resistance of ZM366S dough were higher than those of other doughs, which implied the source of starch also had a significant influence on the rheological properties. CLSM also observed that ZM366S was more closely bound to the gluten protein network. The glutenin macropolymer (GMP) content of ZM366S model dough was the highest, while the SH content was the lowest. Decreases in elasticity, extension and GMP, and small increase in SH content were displayed during dough mixing. Molecular forces were varied with different wheat starch and mixing time. The covalent bond was the main force between ZM103S and gluten, whereas the hydrogen and covalent bonds were the main force between ZM366S or AK58S and gluten. The interactions between ZM366 starch and gluten were stronger than others starch.     

Temperature-induced changes in dough elasticity as a useful tool in defining the firmness of cooked pasta

Semolina with high protein content and strong gluten is recognized as the best raw-material for pasta-products with a good cooking quality, while little consideration has been given to semolina dough elasticity when heating is applied. In this research, a new technique was developed by adapting the Glutograph (Brabender GmbH&Co., Duisburg, Germany) to measure the changes in elasticity induced by heating on a sheeted dough. The information obtained by this procedure was related to the firmness of cooked pasta. Starting from semolina of four durum wheat varieties with differences in protein quantity and quality, dough samples were prepared in a Farinograph at a hydration level of 35 %. Each dough was sheeted by a home-made pasta machine, obtaining disks of 5 cm diameter and 2.1 mm thickness. Stretching (10 s) and relaxation (30 s) cycles were applied repeatedly during the test time, while dough temperature was increased from 30 to 90 °C at 1.2 °C/min. For each peak recorded, stretching and recovery values were calculated and plotted against sample temperature. Both stretching and recovery curves were integrated and the loss of elasticity was calculated. Results showed as high elasticity loss during heating is related to low firmness of the related cooked pasta.     

Applicability of DATEM for Chinese steamed bread made from flours of different gluten qualities

BACKGROUD: The diacetyl tartaric acid ester of monoglycerides (DATEM) is an anionic oil‐in‐water emulsifier. The effects of DATEM on bread vary with the type of flour. However, there is insufficient information concerning the effects of DATEM on the qualities of Chinese steamed bread (CSB) even though it is also sold as a CSB improver. RESULTS: The effects of DATEM on CSB varied with flours. The overall qualities of CSB made from either weak or strong wheat flours were improved by the use of the additive, but the effects for medium strong flours were slight and uncertain. The effects of DATEM on individual parameters, such as specific volume, skin and inner structure, were similar to those on overall quality. The addition of DATEM increased the gluten strength and the dough stability of weak flour, whereas it weakened gluten strength and strengthened dough stability of strong flour. The addition of DATEM weakened the gluten strength and gave variable effects on dough stabilities for two medium strong flours. CONCLUSION: The effects of DATEM on CSB quality varied with flour type, by affecting flour characteristics, such as gluten strength, dough stability and lipid content. Copyright © 2008 Society of Chemical Industry